In IC manufacturing, in particular manufacturing semiconductor components used in devices such as wireless radios, there is a desire to combine higher levels of functionality with a higher level of integration. In high frequency applications achieving higher levels of integration is hindered by increased interference brought on by devices being in closer proximity. For example, obtaining higher levels of integration can be difficult with radios containing components that are electromagnetically sensitive to interference, such as voltage controlled oscillators (VCO), and power amplification chains that produce electromagnetic radiation that may interfere with VCO functions. It is desirable to provide electromagnetic isolation between the two components so that they may be placed in close proximity to each other with reduced risk of interference.
In high frequency applications, another hindrance to integration is thermal coupling between a heat source such as a power amplifier and thermally sensitive components such as Surface Acoustical Wave (SAW) filters and duplexers, whose performance may be degraded by elevated temperatures generated by the power amplifier. Furthermore, heat generated within the power amplifier can cause problems within the power amplifier itself and require additional circuit complexity to deal with thermal runaway, bias compensation, or calibration compensation.
One traditional manufacturing approach is to secure separate metal “cans” over high power and/or electromagnetically sensitive radio devices to provide the necessary isolation. This manufacturing approach occupies excessive area in the form of a grounded solder ring (also known as a “doghouse”). The “cans” also add undesirable size and cost to the final application and may cause electromagnetic coupling feedback loops.